It is accurate to measure blood pressure in the prone position. In fact, blood pressure accuracy is not very much related to body position, as long as the base of the blood pressure is at the same level as the heart when measuring. Blood pressure is most accurate when measured in the prone position, keeping the base of the sphygmomanometer at the same level as, the heart, and the brachial artery. The most common positions used for blood pressure measurement are sitting or supine, but there are differences in the blood pressure measured in these two positions. Most studies have found that diastolic blood pressure measured in the seated position is 5 mmHg higher than in the prone position, systolic blood pressure in the seated and prone positions is not much different, and systolic blood pressure in the prone position is 8 mmHg higher than in the upright position. When measuring blood pressure the balloon should be positioned at the same level as the right atrium, if the upper arm is positioned below the level of the right atrium, the measured value is high, if the upper arm is above the level of the heart, the measured value is low. When measuring blood pressure in the prone position, a small pillow should be used to support the upper arm so that it is at the same height as the mid-axillary line. Regardless of the position, the arms must be supported during blood pressure measurement, especially the elbows, otherwise the systolic blood pressure will increase by about 10% due to isometric muscle contraction. It is recommended that both arms be measured at the first measurement. It is also important that the patient does not drink coffee or alcohol for 30 minutes prior to the blood pressure measurement; does not engage in strenuous activity; is calm, empties the bladder, and sits at rest. Keep quiet during the measurement.